Lubricant



' Patented Aug. 1, 1944 LUBRICANT Arnold J. Morway,

Clark Township,

Union County, and John C. Zimmer, Union, N. J.,.as'- sig'nors to Standard Oil Development Company, acorporatlon of Delaware N Drawing. Application October 4, 1941,

Serial No. 413,650

8 Claims.

The present invention is concerned with the production of improved lubricating grease compositions. lates to a grease composition which is especially adapted for use under extreme variations in climatic conditions, such as wide variations in temperature and humidity. The preferred composition comprises a mineral oil base thickened to a grease consistency with a mixture of saturated fatty acid soaps of lithium and barium.

It is known in the art to prepare various lubrieating grease compositions adapted for particular uses. The uses in which grease compositions are employed present a wide variety of conditions and generally a grease prepared with a given set of conditions in mind is not suitable for use under a different set of conditions. Airplanes are controlled in flight byspecial mechanisms such as rudder, elevators, and ailerons which are adapted to the main portions of the airplane such as fuselage and wings by specially designed hinges. These hinges have metal to metal contact bearing surfaces which offer a very difiicult lubrication problem. Airplanes are operated under the most severe changes in climatic conditions and since the failure of even one part of the mechanism might well result in a catastrophe, it is imperative that all parts of the plane be maintained in as perfect a mechanical condition as possible. In order to be in good mechanical condition all movable parts should be free and well lubricated at all times. It is not uncommon for a plane during a single trip to be subjected to extremely high ground temperatures, subzero temperatures in the upper atmosphere The invention more particularly reas well as conditions of high humidity such as rain, snow, or ice. Any lubricant used upon the control mechanisms of the plane must be capable of withstanding these conditions without disintegration. I

High temperature greases such as the sodium soap greases are known to the art, however they are quite water-soluble and readily disintegrate under humid conditions. Water-insoluble greases, such as the calcium soap greases, are also known, but these compositions will not withstand high temperatures. Aluminum soap greases are also water-insoluble but have a relatively low transient point where they become fluid and run out of the bearing. Barium soap greases are only slowly affected by the presence of water and efiectively withstand elevated temperatures but have the disadvantages of losing their grease structure on standing at lower temperatures and becoming quite stiff and heavy at elevated temperatures.

It'is an object of this invention to produce a grease composition which will provide adequate lubrication at both high and low temperatures and will not decompose in the presence of excessive moisture. This and other objects will be 'apparent'to those skilled in the art upon reading the following description.

The grease composition made in accordance with the present invention comprises essentially a low pour point lubricating mineral oil distillate, J

a lithium soap of a saturated fatty acid and a barium soap of a saturated fatty acid, although it is preferred to use from 10 to 25% of the lithium soap and from 0.50 to 8% of the barium soap based upon the total composition. A small amount of an anti-oxidant, say 0.2%, such as phenyl alpha naphthylamineor a mixture of zinc naphthenate and phenyl alpha naphthylamine, may be used if desired.

Although any of the numerous types of low pour point lubricating oils may be used as the base for compositions made in accordance with this invention, it is preferred touse aCoastal type oil having a viscosity, in-the range of from about 58 seconds to 100 seconds S. U. V. at 100 F. and a cold test below 40 F.

For the formation of the soaps utilized in the production of the. greases any saturated fate or.

saturated fatty acids derived therefrom, such as stearin or stearic acid may be used, although it is preferred to use the saturated acids derived from hydrogenated fish oil.

Any of the methods customarily employed in the compounding of greases may be used in the production of the compositions of this invention.

The soaps maybe produced separately and then mixed with the oil by heat and agitation; or.

preferably the saturated fat or fatty acid to be combined with the lithium and barium may be dissolved in a portion of the lubricating oil by heating the oil sumcietnly to dissolve the fat or acid in the oil, reacting the fat or fatty acid with lithium and barium hydroxides and then the remainder of the lubricating oil is added after which the mixture is brought to a clear solution I by heating, and stirring, generally to atemperature between 360 and 400 F., the anti-oxidant added and the mixture stirred until cool'. Greases of varying consistency to meet the demands of particular conditions may be secured by varying the soap content of the grease within the limits specified. The following examples will serve to illustrate specific embodiments of the invention.

Phenyl alpha naphthylamine 0.2

In compounding the above formula the and approximately V of the oil are charged into a lire-heate kettle equipped with agitators. The

mixture is then heated and stirred to a temperature of about 150' I". or until all the acid is melted and dissolved in the oil and then the lithium hydioxide, dissolved in boiling water, is added to the acid-oil solution. Heating and agitation is continued and the temperature permitted to slowly.

rise until it reaches about 200' F. The barium .hydroxide, dissolved in boiling water is then Free acidity (A. S. T. M.).. per cent (as oleic acid) 0.68 A. B. T. M. dropping point 380 A. B. T. M. penetration at 77 F 240 A. S. T. M. worked penetration at 77 l" 265 About 1% of water can be worked into the grease, by beating in the presence of a relatively large amount of water, however this water will run oil! when the grease is allowed to stand for a few hours and again worked.

Example 2 Per cent Stearlc acid 15.00 Barium hydroxide Ba(OI-I)z-8H:0 0.79 Lithium hydroxide 1.97 Zinc naphthenate 0.40 Phenyl alpha naphthylamine 0.40

Acid treated low cold test transformer oil (58 8. S. U. viscosity at 100?) 81.44

The same method of manufactureis used as that described in Example 1. However the inhibitor (phenyl alpha naphthylamine) and zinc naphthenate are added last at approximately acid 860 1". The kettle must be equipped with a condenser to prevent the boiling of! of the ht hydrocarbon oil used. a

Free acidity per cent (as oleic acid) 0.43

A8.T.M.droppingpo t 300 Penetration 300 Worked penetration. 320

What is claimed is:

1. An improved lubricating grease composition comprising a low pour point lubricating mineral oil distillate, a mixture of lithium and barium soaps of saturated fatty acids in which the amount of lithium soap exceeds the amount of barium soap. mg. 1iatmcompositiorzl as t1giceflliied in claim 1 in which um soap thium soa genated ilsh oil acids. p of hydro 3. A composition as defined by claim 1 inwhich the saturated fatty acids are the acids derived from hydrogenated fish oil.

4. An improved lubricating grease composition comprising a low pour point, low viscosity, lubricating mineral oil distillate and a mixture of lithium and barium soaps of saturated fatty acids in,which the amount of lithium soap exceeds the amount of barium soap.

5. An improved lubricating grease composition comprising from 67 to 89.5% of a low pour point, low viscosity lubricating mineral oil distillate, groin 101:0 2523f a lithium soap of a saturated a yac an rom0.5to8% of of saturated fatty acid. mum on? 6. A composition as defined by claim 5 in which the lithium soap is the lithium soap of hydroenated flsh oil acids. a

7. A composition as defined by claim 5 in which the fatty acids are the acids obtained from hydrggenated fish oil.

An improve lubricating grease com t o consisting of 77.5% of a low viscosity, 1:3 pr m: mineral lubricating oil, 16% of lithium soaps of hydrogenated fish oil acids, 7.57 barium so of hydrogenated fish o u 5 alpha naphthylamine.

- ARNOLD J. MORWAY.

JOHN C. ZIMMER.

oil acids and 0.2% phenyl 

